docs: add plugin setup guide

plugin/lib/commonlibf4/include/RE/S/SneakHandler.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "RE/P/PlayerInputHandler.h"
+
+namespace RE
+{
+	class SneakHandler :
+		public PlayerInputHandler
+	{
+	public:
+		static constexpr auto RTTI{ RTTI::SneakHandler };
+		static constexpr auto VTABLE{ VTABLE::SneakHandler };
+
+		explicit constexpr SneakHandler(PlayerControlsData& a_data) noexcept :
+			PlayerInputHandler(a_data)
+		{}
+	};
+	static_assert(sizeof(SneakHandler) == 0x20);
+}